The coronavirus disease, also known as COVID-19, is primarily considered a respiratory disease due to its effect on the lungs. It causes symptoms such as cough and shortness of breath, as well as severe complications like pneumonia. However, as the COVID-19 pandemic continues, doctors are learning more about SARS-CoV-2, the new type of coronavirus that causes the disease — including its ability to invade other organs, such as the heart.
The cells that bind
The SARS-CoV-2 coronavirus has spiky proteins on its surface. These spikes bind to certain receptors, known as angiotensin converting enzyme-2 (ACE2), on human cells. Once bound to the cell, the virus can enter and infect the cell. ACE2 receptors are found on lung cells, allowing the virus to infect the lungs. But they are also found on other cells in the body, such as heart muscle cells.
“Lung, heart and other cells that have ACE2 receptors on their cell surface are all susceptible to being attacked by the SARS-CoV-2 virus,” says Dr. Nassir Azimi, a cardiologist affiliated with Sharp Grossmont Hospital. “This is why we sometimes see patients with COVID-19 experiencing respiratory events, cardiovascular events and systemic illness.”
An overworked, inflamed heart
When a person becomes infected with the coronavirus, heart function may decrease, leading to various cardiovascular conditions.
For instance, during an infection, the heart and lungs must work harder to pump oxygenated blood to the body, all while defending against the virus. For older individuals with existing cardiovascular disease, such as coronary heart disease or high blood pressure, this puts an increased workload on an already vulnerable heart, which can lead to heart failure.
Heart failure can also occur in younger patients or those without existing cardiovascular conditions.
“When a viral infection causes inflammation of the heart muscle, this condition is known as myocarditis,” says Dr. Alexandra Kharazi, a cardiovascular surgeon affiliated with Sharp Grossmont Hospital. “When the immune system overreacts in its fight against the virus, it results in a systemic inflammatory response, known as a cytokine storm. Both instances can cause severe heart inflammation and dysfunction.”
So what happens to a heart damaged by COVID-19? While most patients recover from the disease, some patients experience more severe complications. As global health data pour in, researchers have found that patients with COVID-19 who experienced heart damage due to infection were more likely to die, compared to those who did not experience heart damage from COVID-19.
Studies have also found that the risk of mortality or serious complications from the disease increased for those who are male, 65 years or older, or had existing conditions, such as high blood pressure, diabetes, cardiovascular disease and stroke.
“People with existing cardiovascular disease are more likely to encounter severe complications if they get COVID-19, let alone any viral disease,” says Dr. Azimi. “For example, we have seen that those with diabetes who get COVID-19 are more likely to have serious multilobar pneumonia and defuse lung inflammation, leading to respiratory failure requiring intubation and ventilation. Due to the high inflammatory burden, there is potential for coronary plaque disruption in blood vessels of patients with coronary artery disease. The plaques break off and can cause clotting that leads to blockages, leading to heart attacks or strokes.”
According to Dr. Azimi, there are many reports from China, Italy and the United States of increased clotting risk, not only in the blood vessels of the heart and brain, but also in the veins of the legs. These clots have the potential to break off and end up in the lung arteries, which can be fatal.
According to doctors, once someone has recovered from COVID-19, there is still a possibility that there could be long-term heart damage as a result from the disease.
“As we continue to learn more about how the virus acts during infection, we are also trying to understand what lingering effects it could have once a patient recovers,” says Dr. Kharazi. “Whether permanent damage to the heart occurs may be dependent on how the heart became damaged in the first place, anatomy, reaction to therapies, and other factors. This is a novel virus affecting the human species, so it will take some time to collect and synthesize the data from infection to recovery, and perhaps beyond. Although the long-term effects to the heart caused by the disease are largely unknown at this time, we have current cardiovascular therapies available to effectively treat many heart conditions.”